It is known to use hydrogen peroxide (H2O2) in sterilization and other processes. In a sterilization process, liquid hydrogen peroxide is vaporized to form vaporized hydrogen peroxide (VHP). The vaporized hydrogen peroxide is typically produced from a liquid mixture of hydrogen peroxide and water. Care must be taken when vaporizing this mixture due to the difference in the boiling points between water and hydrogen peroxide. In this respect, water boils at 100° C., whereas pure hydrogen peroxide boils at 150° C. Accordingly, when a mixture of water and hydrogen peroxide is vaporized, the water tends to boil before the hydrogen peroxide unless the mixture is flash vaporized. In conventional systems, flash vaporization is accomplished by dripping a small amount of the water and the hydrogen peroxide mixture on a hot surface. Air is directed over the hot surface to conduct away the vaporized hydrogen peroxide.
U.S. Pat. No. 2,491,732 discloses a conventional vaporized hydrogen peroxide (VHP) vaporizer. A problem with the aforementioned drip method of vaporization is that a hot surface must be maintained to vaporize the liquid hydrogen peroxide and water mixture. Testing has shown that an injection rate of up to 5 grams per minute per injection port can be achieved with current drip-method vaporizers. At higher injection rates, individual droplets can no longer be maintained. In other words, the drip-type vaporizer is limited in the amount of vaporized hydrogen peroxide it can produce within given size limits. This limitation prevents drip-type vaporizers from being used in certain high volume sterilizing processes where it is necessary to sterilize large numbers of articles and devices in a short period of time.
Another problem with vaporized hydrogen peroxide decontamination systems is preventing condensation of the vaporized hydrogen peroxide on the articles or surfaces to be decontaminated.
It is therefore desirable to have a high-capacity vaporized hydrogen peroxide generator capable of generating high volumes of vaporized hydrogen peroxide at concentration levels that will not condensate on the articles or surfaces to be decontaminated.
The present invention provides a hydrogen peroxide vaporizer capable of generating large volumes of vaporized hydrogen peroxide at concentration levels that will not condensate on the articles or surfaces to be decontaminated.